J. Phys. IV France
Volume 112, October 2003
Page(s) 523 - 527

J. Phys. IV France
112 (2003) 523
DOI: 10.1051/jp4:2003939

Stabilization of martensite in ${\mathsf \alpha/\beta}$ microstructure of a Cu-Zn-AI shape-memory alloy

S. Longauer, M. Vojtko, G. Janak and M. Longauerova

Department of Materials Science, Faculty of Metallurgy, Technical University of Kosice, Letna 9, 04200 Kosice, Slovak Republic

Direct quenching of samples of Cu22Zn4.6A1 alloy from temperatures of an $\alpha/\beta$-field to room temperature causes strong stabilization of martensite in samples with A $_{\rm s}$ (the temperature at which transformation to austenite begins) above room temperature. This can be removed by immediate heating of samples at 170°C after quenching from T $_{\rm Q}$ between 630 and 690°C. Shift of A $_{\rm s}$ to the nominal value depends on time of annealing. In samples quenched from higher temperatures over 690°C the stabilization was not removed. The observation of in situ deformation of martensite in upquenched samples supports the explanation [2] of the decreasing shape memory with increasing quenching temperature by changes in stacking fault energy.

© EDP Sciences 2003